The recent trends toward early detection and increasingly conservative treatments for breast cancer have led to initial exploration of cryotherapeutic approaches. Cryolumpectomies help to ensure clear surgical margins. Cryosurgical approaches are minimally invasive and known for minimal scarring, thus are highly appealing. Current cryotherapy probes, however, puncture the tumor capsule increasing the risk of spreading cancerous cells and are limited in their ability to operate near sensitive tissues due to the risk of thermal injury. The proposed cryotherapy probe protects sensitive nearby tissues from freezing, measures the actual temperatures achieved, controls the size of the freeze zone and can be inserted alongside the tumor without puncturing the capsule. In Phase I, a proof-of-principle probe will be fabricated and tested in vitro. In Phase II, a prototype probe will be built and tested in vivo in a clinical setting. PROPOSED COMMERCIAL APPLICATIONS: The proposed cryotherapy probe has strong commercial potential. Our commercialization strategy is based on licensing the technology developed under this program to an existing vendor of medical equipment.